Name __________________________________
Guided Notes: Electrons in Atoms
Draw an atom of lithium.
How did scientists figure out the electron energy levels? Can they see them? _________
Question for the day: How did scientists figure out that electrons are in certain energy levels?
Scientists got clues from ____________________. Atoms absorb and emit it in distinct ways.
What does a prism do? A prism breaks light into its ________________________________.
Sunlight has a continuous spectrum. Sketch a continuous spectrum here:
A _____________ is another example of the continuous spectrum of sunlight. All the colors blend into each
other. Every possible energy level of light is present.
When scientists look at the light coming off a pure element, they don’t see a continuous spectrum, they see a
____________ spectrum.
Sketch the line spectrum of hydrogen. But leave some space to add more to it later on.
Every element has a unique line spectrum. Name an important application of this discovery.
_______________________________________________________________________________________
As you know, the color of a light corresponds to its ______________________________. Atoms only emit
light of certain ___________________________. But why don’t they emit light of all the energies?
Neils Bohr came up with a radical answer. Electrons can orbit the nucleus only in certain allowed energy
levels.
Think of it like _________________ on a ladder. You can be on one rung, or another rung, but not really
between rungs.
Electrons can be in one ___________________________ or jump to another _______________________,
but they’re not allowed to be in between the allowed energy levels. Electrons can’t be just anywhere.
Name __________________________________
It takes energy to move an electron away from the nucleus. Why? _______________________________
Conversely, if an electron moves back closer to the nucleus, energy is ____________________________.
Remember, energy is required to move an electron to a _________________ energy level, and energy is
released when an electron moves to a ____________________ energy level.
The fact that atoms give off characteristic colors of light (________________________) provides clues
about how electrons are arranged in atoms.
The line spectra gave rise to two important ideas:
1. Electrons exist only in certain _______________________________ around the nucleus.
2. Energy is ____________________________ when an electron moves to a higher level;
energy is ________________________ when an electron moves to a lower level.
Go back to the hydrogen line spectrum you drew earlier, and label each line with the energy change for the
electron that it corresponds to.
Copy the bohr model of the hydrogen atom below, showing the changes in energy that show up as colored
lines in the line spectrum: